Reduced thermal conductivity in Nnnostructured AgSbTe_(2) thermoelectric material, obtained by Arc-Melting

Abstract

AgSbTe_(2) intermetallic compound is a promising thermoelectric material. It has also been described as necessary to obtain LAST and TAGS alloys, some of the best performing thermoelectrics of the last decades. Due to the random location of Ag and Sb atoms in the crystal structure, the electronic structure is highly influenced by the atomic ordering of these atoms and makes the accurate determination of the Ag/Sb occupancy of paramount importance. We report on the synthesis of polycrystalline AgSbTe_(2) by arc-melting, yielding nanostructured dense pellets. SEM images show a conspicuous layered nanostructuration, with a layer thickness of 25-30 nm. Neutron powder diffraction data show that AgSbTe_(2) crystalizes in the cubic Pm-3m space group, with a slight deficiency of Te, probably due to volatilization during the arc-melting process. The transport properties show some anomalies at similar to 600 K, which can be related to the onset temperature for atomic ordering. The average thermoelectric figure of merit remains around similar to 0.6 from similar to 550 up to similar to 680 K.